In which activities is speed helpful? Running track Swimming Riding in a bike race All of the above

all of the above

Explanation:

they all require speed to beat

All of the above

Explanation:

if your taking any kind of quiz or even review and there's a choice of "all of the above" it's always right because that answer won't be on every question!

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

no sign of dia of fuel cell